Various electronic apparatus capable of handling a video image in the form of digital data are widely used nowadays. For example, if carrying a mobile electronic apparatus having a wireless network function, the user can view latest news images etc. even when the user is out or is moving. Furthermore, recently, personal computers having a TV function for viewing, recording, and reproducing digital TV broadcast data have became widely used.
Digital processing on a video image, that is, coding, transmission/reception, and decoding of a video image, imposes a heavy load on a processor and a network. In view of this, various schemes for reducing the load of digital processing on a video image have been proposed so far (refer to JP-A-2004-357205, for example).
In the publication, JP-A-2004-357205, when the transmission bandwidth is limited in stream delivery, image quality deterioration that is caused by decoding on the reception side is suppressed by giving higher priority to packets (corresponding to slices) having large coding information amounts per macroblock irrespective of the coding prediction method, selecting transmittable video packets from the video packets in each frame according to priority ranks, and sending them. In performing N-fold fast reproduction, fast reproduction frames are constructed and reproduced by selecting video packets that can be reproduced fast are selected according to packet priority ranks in both of P frames and B frames. Therefore, serious image quality deterioration occurs if coding information of an I frame (intrapicture predictive coding data) or a P frame as a reference frame is lost according to priority ranks. Furthermore, this conventional technique is associated with a problem that it cannot accommodate a case that necessary processing cannot be performed on the transmission side (coding side) as in the case of handling broadcast data because it is necessary to determine priority ranks on the decoding side and reconstruct data on the reception side.